btrfs: add sha256 to checksumming algorithm

Add sha256 to the list of possible checksumming algorithms used by BTRFS.
Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/Kconfig

@@ -6,6 +6,7 @@ config BTRFS_FS
 	select CRYPTO_CRC32C
 	select LIBCRC32C
 	select CRYPTO_XXHASH
+	select CRYPTO_SHA256
 	select ZLIB_INFLATE
 	select ZLIB_DEFLATE
 	select LZO_COMPRESS

fs/btrfs/ctree.c

@@ -35,6 +35,7 @@ static const struct btrfs_csums {
 } btrfs_csums[] = {
 	[BTRFS_CSUM_TYPE_CRC32] = { .size = 4, .name = "crc32c" },
 	[BTRFS_CSUM_TYPE_XXHASH] = { .size = 8, .name = "xxhash64" },
+	[BTRFS_CSUM_TYPE_SHA256] = { .size = 32, .name = "sha256" },
 };
 
 int btrfs_super_csum_size(const struct btrfs_super_block *s)

fs/btrfs/disk-io.c

@@ -353,6 +353,7 @@ static bool btrfs_supported_super_csum(u16 csum_type)
 	switch (csum_type) {
 	case BTRFS_CSUM_TYPE_CRC32:
 	case BTRFS_CSUM_TYPE_XXHASH:
+	case BTRFS_CSUM_TYPE_SHA256:
 		return true;
 	default:
 		return false;

fs/btrfs/super.c

@@ -2463,3 +2463,4 @@ module_exit(exit_btrfs_fs)
 MODULE_LICENSE("GPL");
 MODULE_SOFTDEP("pre: crc32c");
 MODULE_SOFTDEP("pre: xxhash64");
+MODULE_SOFTDEP("pre: sha256");

include/uapi/linux/btrfs_tree.h

@@ -303,6 +303,7 @@
 enum btrfs_csum_type {
 	BTRFS_CSUM_TYPE_CRC32	= 0,
 	BTRFS_CSUM_TYPE_XXHASH	= 1,
+	BTRFS_CSUM_TYPE_SHA256	= 2,
 };
 
 /*